bnelson

my fsa crank worked it self loose.Is there something I need to do?I tightened but then it does not spin freely,Thanks

frankenmike 

I assume you've got the external bearing type. The two pinch bolts hold everything together, the big center bolt adjusts the bearings. Loosen the pinch bolts. Tighten the big center bolt until there is no play(looseness) but the cranks turn freely. Now tighten the pinch bolts. Good to go. My fsa cranks come loose every so often. Until I can afford a better crankset(i.e. one that won't come loose on its own), I just make sure to check it regularly.

bnelson

there are no pinch bolts just the center one on the nondrive side

jsharr

Probably need to go the FSA website then and find your crank and the tech docs for it. Or post pics or model no. of the crank, both sides.

https://www.fullspeedahead.com/fly.as...1&languageid=1

CACycling

I assume you have a FSA SL-K crankset. For the most part, once it comes loose under load, it's time to shop for a new crankset. Mine made it all of 250 miles.

jasonrobo02

Follow instructions on the FSA site. Mine has never loosened itself over 1000's of miles.

operator

Uh no.

If the cranks came loose, and the OP only has a center bolt, it's 8mm. If it's an 8mm center bolt then tighten that backup to torque SPEC. Use a torque wrench if you are unfamiliar with proper torque. Unless the threads were stripped/damaged there is no reason why that crank wouldn't stay on, even if it came loose.

CACycling

The FSA SL-K is a two-piece, external BB crankset that has a history of coming loose (even when the center bolt is properly torqued when installed) and ruining the interface between the arm and spindle. FSA later included thread lock with these cranksets. Mine was one installed without and could not be tightened adequately once it came loose. It was replaced under warranty.

DSchlichting

Loctite 641 is not a threadlock, but a (drum roll, please) . . . a "retaining compound", presumably to take up whatever slop with which these were manufactured. I have a Team Issue Mega Exo, and while I like the crankset itself, most of the components are in the POS category from the bearings to the chainring bolts that shear well below the prescribed torque spec. With that said, in my experience, if this is installed exactly as per FSA instructions --and I think the wave washers are a newer thing, too,-- it will stay together.

CACycling

Mine was before the problem was widespread so the "retaining compound" wasn't supplied yet. Treadlock/retaining compound/whatever, when the crank arm comes loose and replacement is the only option after 250 miles on a new bike, I'll stay away from FSA thank you very much.

dscheidt

Yes, so? That mean it can't lock threads? It's normally used to do things like retain press fit bearings on shafts, or press pit retaining pins and the like. Loctite 641 is an anaerobic acrylic. Same as Loctite's threadlocking compounds. It performs pretty much the same as 242 does; it's got slightly different solvent compatability (which I'm far too lzy to look up for you.). And it 's yellow. Other than that, it's acting as a thread locker. I have no idea why they chose that product, instead of something the spec sheet calls a thread locker, but I'd bet they did it in co-operation with Henckel's technical application people.